1. Field of the Invention
The present invention relates to a Corynebacterium sp. microorganism modified to utilize xylose and a method for producing L-lysine using the same.
2. Description of the Related Art
Industrial microorganisms utilize sugar such as glucose, fructose, and sucrose as a carbon source. Agricultural products are usually used as feedstock to obtain these carbon sources, but they are expensive and are more valuable as food. Recently, instead of using agricultural products as traditional feedstock, cellulosic biomass including agricultural waste or woody waste, industrial waste, etc. has attracted attention as an ideal sugar raw material for fermentation, because it has the advantages of low cost and abundant supply.
Among them, xylose is the second most abundant lignocellulosic carbohydrate in nature, and is a representative cellulosic biomass. Useful materials have been produced from xylose using industrial microorganisms. For example, a method of producing L-amino acid is known, by culturing a Escherichia sp. strain in a medium containing a mixture of pentoses including glucose and xylose, wherein the stain is modified to increase expression of xylABFGHR gene cluster encoding an enzyme (xylosidase) hydrolyzing xyloside, which is a glycoside derived from xylose, and then recovering L-amino acid from the medium (Japanese Patent No. 4665567).
On the other hand, a Coryneform bacteria, Corynebacterium glutamicum, is known as a Gram-positive strain used in production of various L-amino acids. As described above, because xylose is the second most abundant lignocellulosic carbohydrate in nature, it is expected that L-amino acids such as L-lysine can be more economically produced from Corynebacterium glutamicum by using xylose. However, Corynebacterium glutamicum does not have important genes which are involved in the metabolic pathway of xylose, which is a pentose, and thus there is a problem that L-amino acid cannot be produced from Corynebacterium glutamicum by using xylose. To solve this problem, there has been a report that Corynebacterium glutamicum is modified to be able to utilize xylose by introducing xylose isomerase (XylA) and xylulokinase (XylB) derived from Escherichia coli (Kawaguchi et al., AEM 72:3418-3428, 2006).
The present inventors have made extensive efforts to produce L-amino acid in a more economical manner, and as a result, they found that when XylA and XylB-encoding genes derived from Erwinia carotovora are introduced into Corynebacterium glutamicum, the variant is able to utilize xylose to produce L-lysine and also shows more improved xylose-utilizing ability than the previously known Coryneform microorganism introduced with xylA and xylB derived from Escherichia coli, thereby completing the present invention.